PHP：嵌套 foreach 循環的問題 (PHP: Issue with nested foreach loops)

問題描述

PHP：嵌套 foreach 循環的問題 (PHP: Issue with nested foreach loops)

基本上，我正在嘗試從多個 xPath 查詢中提取數據，並將從每個文件中提取的數據提交到 CSV 中的一行。我遇到的問題是遍歷特定的 xPath 查詢並將其結果連接到一行。

我有以下代碼：

$category_titles = $xpath‑>query('//*[@id="shopMain"]/div/div/h1');
$category_introduction = $xpath‑>query('//*[@id="shopMain"]/div/div/p'); 

if($category_title){

  foreach($category_title){
        foreach($category_introduction as $node){
            $test .= $node‑>nodeValue;
            var_dump($test);
            continue();
         }  

            $test = '':
     }  
}

我正在嘗試為每個 $category_title 循環 $category_introduction 查詢和連接每個

元素。然後，當所有

標記都已連接時，我嘗試跳出循環，並僅在清除 $test 的情況下重複該過程。誰能建議我如何在嵌套的 foreach 循環中做到這一點？我'

參考解法

方法 1:

i think the issue is with if condition and foreach loop because in if condition and foreach loop you have declared wrong variable

Try this

if($category_titles) 

and

foreach($category_titles)

Instead of

if($category_title)

and

foreach($category_title)

方法 2:

In addition to Umesh Chauhans answer.

I see several problems with your code:

1. $test is not initialized.
2. The if($category_title) only checks for the values existence. Not for it to be iterable. You might want to use is_array().
3. Your first foreach loop does not use the item to be iterated (the as $value part is missing). See PHP doc: foreach (array_expression as $value) statement;
4. continue is a keyword not a function, so omit the (), look up the PHP doc as well

In general you might want to query $xpath‑>query('//*[@id="shopMain"]/div/div'); and then do subqueries.

(by Liam Fell、Umesh Chauhan、Metterschling)

參考文件

1. PHP: Issue with nested foreach loops (CC BY‑SA 2.5/3.0/4.0)